This invention relates to a process for preparing gamma-lactones by the catalyzed oxyacylation of alpha-olefins.
Lactones are important industrial chemical products which are useful in a variety of applications. Gamma-lactones, and in particular gamma-butyrolactones, are particularly important as intermediates in the production of diol compounds such as 1,4-butanediol.
There are various known methods to prepare lactones as shown in "Advanced Organic Chemistry" by Fieser and Fieser, Reinhold Book Corporation, 1968, on pages 572-575. Thus, for example, gamma-lactones may be prepared from gamma-hydroxy acids by dehydration or by isomerization of unsaturated acids by heat or by treatment with hydrobromic or sulfuric acid. U.S. Pat. No. 3,890,361 to Kanetaka et al. describes the production of gamma-butyrolactones by catalytic hydrogenation of dicarboxylic anhydrides using a special nickel catalyst.
The preparation of lactones from olefins is also known. In an article by Heiba et al. entitled "Oxidation By Metal Salts. X. One-Step Synthesis of Gamma-Lactones from Olefins", Journal of the American Chemical Society/96:26/Dec. 25, 1974, the reaction of an olefin and a carboxylic acid having an alpha-hydrogen atom in the presence of stoichiometric amounts of a higher valent metal salt or oxide of manganese, cerium, or vanadium oxidant is disclosed. The reaction is carried out in a refluxing system at a temperature of 120.degree.-180.degree. C. Similar reactions using the vanadium catalyst are shown in Chemical Abstracts, Volume 72, 1970, 66402a, Volume 82, 1975, 5760a and Volume 84, 1976, 150211t.
It is an object of this invention to provide an improved process for the preparation of gamma-lactones from olefins. Other objects and advantages will become apparent from the following description.